404 MR, HANCOCK ON THE ANATOMY OF THE FRESHWATER, ETC. 
Fig. 5.—Enlarged view of a cell of Plumatella Allmani exhibiting reproduc- 
tive organs: a, base of oral arms; 6, esophagus; c, stomach; 
d, intestine ; e¢ e’, ovary; f, egg nearly mature, still attached to 
ditto; g, an egg just forming likewise attached to ovary; 
hh, two filaments attached to the stomach, probably connected 
with the reproductive system; 2 2, the two bundles of retractor 
muscles; j, outer wall of cell; 4, lining membrane or tunic. 
PLATE V. 
Fig. 1.—Enlarged view of a cell of Paludicella procumbens seen as a trans- 
parent object, the polype being exserted: aa, outer wall of cell ; 
6 6 6, lining membrane or tunic; c, tubular orifice; d, mem- 
branous cup surmounting ditto; e, tentacular disc; 7, tentacles ; 
g, pharyngeal swelling; A, esophagus; 7, stomach; 7, intestine; 
k, enlargement at commencement of ditto; /, anus; m, supposed 
ovary; x, filament attached to the lower extremity of stomach, 
probably connected with the reproductive system; 0, polype 
retractor muscles; p p, inferior tube-retractors; g, two fibres 
of superior tube-retractors; 77, muscles to prevent the complete 
inversion of tentacular sheath; s, tentacular sheath doubled 
upon itself; ¢ parietal muscles; u, end walls of two cells 
abutting against each other. 
Fig. 2—Enlarged view of a single cell of P. procumbens with polype re- 
tracted: a, outer wall of cell; b, lining membrane of ditto; 
c, retracted tubular orifice; d, tentacles; dd’, tentacular 
sheath; e, esophagus ; /, cardiac orifice; g, stomach; h, intes- 
tine; 7, enlarged portion of ditto; 7, supposed ovary doubled 
upon itself; 4, filament attached to lower end of stomach, pro- 
bably connected with reproductive system ; /-l, polype retractor 
muscles; m m, inferior tube-retractors; m n, superior tube- 
retractors; o, sphincter muscles for closing orifice; p, ditto 
ditto; g g, muscles to prevent complete inversion of tentacular 
sheath; 7, end wall of cell formed by the tunic exhibiting en- 
largement in the centre. 
Fig. 8.—End of retracted tube of P. procumbens exhibiting the manner in 
which it folds in. 
Fig. 4.—Termination of a branch of P. procumbens comprising two cells in 
different stages of development: a, outer wall of cell in fourth 
stage of development; 6, lining membrane of ditto; 6’, blind 
termination of ditto ditto; c, place of future orifice ; d, tentacles 
of polype in state of development ; e, cesophagus; 7, stomach ; 
g, intestine; A, lower productive organ; 2, tentacular sheath ; 
J, polype retractor muscles; 4, tube-retractors; J, new cell in 
first or earliest stage of development, exhibiting lining membrane 
and external wall; m, nucleated cells in lining membrane. 
-Fig. 5.—Two terminal cells of P. procumbens containing buds in different 
stages of development: a, tentacles of bud far advanced or in 
fifth stage of development; a/, tentacular sheath; 6, esophagus; 
c, stomach; d, intestine; e, anus; /, lower reproductive organ ; 
g, polype-retractors; h, parietal muscles; 2, tube-retractors ; 
Jj, tube just forming ; &, outer wall of last-formed cell exhibiting 
bud in second stage of development; 4, lining membrane of 
ditto; m, bud as it appears at first. 
Fig. 6.—Terminal cell exhibiting bud in third stage of development: 
a, outer wall of cell; 6, lining membrane; c, bud; d, tentacular 
sheath; e, polype-retractors just making their appearance. 
